1. Field of the Invention
The present invention relates to a separator for separating a mixture of solid and liquid, in particular waste water originating from dental practice, with an inlet for the mixture that is to be separated, with an outlet for the liquid that has been separated off, with a full-casing centrifuge which has an inlet opening arranged on the top, a transfer opening that is associated with the outlet for the liquid, and a drain for the solids, with a removable settling tank that is arranged beneath the outlet for the solids and used for the solids that run off after each centrifuging phase as a result of gravity, with a residual fluid fraction, with a pump that has a suction pipe that extends downwards into the settling tank to a point above a maximum preset sedimentation level (into the settling tank), and with a line that connects the pressure side of the pump with the inlet opening of the centrifuge.
2. Description of the Related Art
A separator of this type is described, for example, in FIG. 3 of WO-A-89/04152. In this separator, the inlet for the mixture that is to be separated, which originates, for example, from a dental suction system or from a rinse basin, is located in the separator on the top of the centrifuge and opens out into a mixture inlet chamber from which it moves into the centrifuge. The solids that flow out together with the residual liquid collect in the settling tank, from which the remaining liquid is moved upwards and into the mixture inlet by means of the pump. When a preset level of sediment is reached, the settling tank is removed and emptied and replaced by an empty tank.
It has been shown that a primary screen is useful or even necessary in the feed line to the mixture inlet in order to prevent particles that are too large from entering the centrifuge. Such particles come mainly from the rinsing basin, when the mouth is rinsed. Larger particles of this kind, such as bone or tooth fragments, pieces of amalgam, or even cellular material, can unbalance the centrifuge if they are not removed, or can impair the degree of purity of the liquid.
For this reason, it is the task of the present invention to so configure a separator of the type described in the introduction hereto that only particles of solid material that are of a size that can be processed without any difficulty are allowed into the centrifuge.